This invention relates to forging machines having die holder lateral adjustment.
For the forging of workpieces having a distinct longitudinal axis, forging machines are employed which are provided with four rams equipped with dies, arranged in an X arrangement within a plane, offset at 90.degree. from one another, acting radially on the workpiece which is guided along the system axis. A forging machine of this generic type is known from European Patent EP 0 228 030 B1 and also U.S. Pat. Nos. 4,796,456 and 4,831,864, in which the rams guided in the machine frame constitute parts (single-piece or in combination) of piston-and-cylinder units with a stroke corresponding to the working stroke of the ram, and are adjustable in terms of their stroking position by crossheads which are adjustable relative to the machine frame and support the piston-and-cylinder units. The rams with the dies, which are transversely adjustable within their common plane by means of die holders mounted on the rams, are adjustable and fixable by actuator means, acting on the die holders, as a function of the stroke end position setting of the rams, such that the dies form a closed pass contour at their respective stroke end positions, with that part of their working surface protruding beyond the pass contour dimension overlapping a side surface of an adjacent die. The actuator means, the end members (toothed racks, link guides) of which are connected to the holders, are driven via shafts by motors which are secured to the adjustable crossheads, such that only the ram working stroke has to be accommodated in the drive connection from the motor to the end member of the actuator means.
In order to accommodate the shaft provided in the drive connection, the ram and its piston-and-cylinder unit must be provided with central through openings, or the shafts have to be arranged laterally next to the rams. The central arrangement of the shafts requires the provision of hollow shafts in the piston-and-cylinder units in order to be able to seal the piston and cylinder with respect to one another and to the central through openings, in the manner apparent from FIGS. 2, 3 and 6 of EP 0 228 030 B1. The constructional expense is correspondingly high, and accessibility to the components is impaired. Where the shafts are arranged laterally next to the rams, the drive connections between the shafts and end members of the actuator means cause difficulties, with the added problem that these components are exposed to the radiation heat and flying scale from the workpiece, as is apparent from FIG. 7 and 8 of EP 0 228 030 B1.